Lubricant compositions



3,531,411 LUBRICANT COMPOSITIONS Albert Benson, Fairlawn, and GerhartKarg, Pompton Lakes, N.J., assignors to Witco Chemical Company, Inc.,New York, N.Y., a corporation of Delaware N Drawing. Filed Jan. 17,1968, Ser. No. 698,397 Int. Cl. Cm 3/02, 3/40 US. Cl. 25232.5 7 ClaimsABSTRACT OF THE DISCLOSURE This invention relates to novel lubricantcompositions having improved properties in regard to chemical stability,corrosion inhibition, reduction of foaming tendencies, and anti-wearprotection, for particular use in extreme pressure applications.

Lubricating compositions comprising oil base vehicles and lubricatingcompositions comprising water base vehicles and containing certainphosphate esters are known to the art and are disclosed in such US.patents as, for instance, Nos. 3,010,903; 3,169,923; 3,203,895; 3,297,-098 and 3,310,489. In this last-mentioned patent, lubricatingcompositions are disclosed for use in metal working operations which maycomprise water solutions containing from about 0.001 to about by weight,of various amine, notably triethanolamine, reaction products of certainphosphate esters, namely, phosphate monoand diesters of ethylene oxideadducts of hydroxylic compounds containing a hydrocarbon group having atleast 9 aliphatic carbon atoms, said esters being exemplified by thephosphate monoand di-esters of a 4 mol or 10 mol ethylene oxide adductof nonylphenol, or phosphate monoand di-esters of other nonionicsurfactant ethylene oxide adducts of long chain alcohols or alkyl henolscontaining, as indicated above a hydrocarbon group having at least 9aliphatic carbon atoms. The patent emphasizes the importance of thepresence of a hydrocarbon group having at least 9 aliphatic carbon atomsin the phosphate esters in order to obtain compositions which are usefulfor the purposes of the patent and wherein metal staining is avoided.

For certain metal working applications, such as using a lubricant as asynthetic cutting fluid, a certain combination of properties is of theutmost importance. These properties include stability at hightemperature, high loadcarrying capacity, protection against wear andcorrosion and low foaming tendency. Low foam is a particularly importantproperty for extreme pressure lubricants used in metalworking operationsin order to insure the avoidance of blockage of the circulation systemby air entrainment and to achieve good visibility at the work area.

In accordance with the present invention it has been discovered thataqueous solutions of amine salts of monoor di-esters (and mixturesthereof) of phosphoric acid and a 1 to 6 mole ethylene oxide adduct ofphenol have an unexpected combination of properties in regard to loadcarrying ability, low foaming, thermal stability and corrosioninhibition which render said solutions extremely effective as extremepressure lubricants.

Generally, the phosphate esters utilized in the practice of the presentinvention can be prepared by reacting 1 States Patent 0 3,531,411Patented Sept. 29, 1970 mole of P 0 with 2 to 4.5 moles, preferablyabout 3 moles, of an adduct or condensation product of 1 to 6 moles,preferably about 3 moles, of ethylene oxide with 1 mole of phenol, usingthe type of procedure for the production of phosphate esters disclosed,for instance, in US. Pats. Nos. 2,441,295; 2,676,975; 2,701,258;3,004,056 and 3,004,057; and German Pat. No. 696,317.

It has been found that, to achieve the desired characteristics, thephenol adduct from which the phosphate esters are prepared shouldcontain no more than about 6 moles of ethylene oxide per mole of phenol.For example, the phosphate ester of an 8 mole ethylene oxide adduct ofphenol has been found to exhibit relatively inferior properties inregard to foaming characteristicts and load carrying ability whencompared, for example, with the phosphoric acid ester of a 4 moleethylene oxide adduct of phenol. Minor proportions of propylene oxide,for instance, can be used to replace a part of the ethylene oxide inmaking the adducts but, in general, the amount of propylene oxideutilized should not exceed about 20%, by weight, of the ethylene oxide.It is especially advantageous to use ethylene oxide solely as thealkylene oxide in making the adducts of phenol used in producing thephosphate esters which are employed in the compositions of the presentinvention.

The phosphate esters utilized in the practice of the present inventioncan be represented by the following formulae, (I) being the mono-esterand (II) being the di-ester:

where n is an integer from 1 to about 6, preferably 3 to 5 andparticularly about 4. It will be noted that said esters are devoid ofany hydrocarbon group containing at least 9 aliphatic carbon atoms.

The amine which is utilized as a reactant or to form a salt with thephosphate ester in the lubricating compositions of the present inventioncan be selected from a wide group so long as water-solubility of theproduct is obtained. Thus, said amines can be primary, secondary ortertiary, straight chain or branched chain, saturated or unsaturated,and can be of aliphatic, araliphatic or aro matic character. Of especialvalue are the hydroxyalkyl amines or alkanolamines, such as mono-, diandtri-ethanolamine or mixtures thereof, particularly triethanolamine.Other illustrative examples of amines which can be used aredimethylamine; diethylamine; triethylamine; propylamine;monoisopropylamine, diisopropylamine, triisopropylamine, and commercialmixtures of said isopropylamines; butyl amine, amyl amine;monoisopropanolamine, diisopropanolamine, triisopropanolamine andcommercial mixtures of said isopropanolamines; polyamines such asaminoethyl ethanolamine, ethylenediamine, diethylenetriamine,hydroxyethyl ethylenediamine, and hexamethylenediamine; hexylamine;cyclohexylamine; methylcyclohexylamine; alkyl alkanolamines such asethyl diethanolamine and diethyl ethanolamine; piperidine; 2-amino 2methyl-l-propanol; 2-amino-1- butanol; methyl piperidine; benzylamine,naphthylamine, aniline, methyl aniline; and compatible mixtures of anytwo or more thereof.

Only minor amounts of the reaction product of the amine and thephosphate ester are necessary in order to produce a lubricant having theaforementioned superior characteristics. While the preferredconcentration is of the order of about 0.1 to 0.2 weight percent inwater, concentrations as low as 0.01% and as high as several percent,for instance, to can be used but such higher concentrations areunnecessary.

Supplemental ingredients for obtaining special effects can be added inminor proportions, if desired, examples of which are, for instance,corrosion inhibitors for certain metals, load support agents, etc.

The invention is further illustrated but not limited by the followingexamples wherein all percentages reported are by weight.

Example I A 0.1% solution in water of the triethanolamine salt of aphosphate ester, prepared by reacting P 0 with a 4 mole ethylene oxideadduct of phenol, was subjected to the Falex Load Test Method todemonstrate load carrying properties. For purposes of comparison, datafor an 8 mole ethylene oxide phenol phosphate ester, also as a 0.1%triethanolamine salt solution in water, is included. Briefly, the testemploys a Faville LeVally lubricant tester equipped with an automaticloading device, load gauge, torque indicating gauge, brass shear pins,steel journals and steel V bearing blocks. The lubricant is placed inthe machine and torque readings are taken at 250 lb. increments untilfailure occurs or the maximum load of 4500 lbs. is reached. Failure isindicated either by sudden shearing of the brass locking pins or wearoccurring at such a rate that the loading ratchet is not able tomaintain the load and the load actually decreases. The results aresummarized in the following table.

FALEX WEAR TEST DATA Extreme Pressure Load Failure at: 1,750 lbs; 1,000lbs. Conditions:

Temperature: 150 F. Time: 2 min. each at 250, 500 and 750 lbs, and min.at 1,000 lbs.

Torque (inch-lbs.)

Phenol plus Phenol plus 4mole E.O. 8Inole E.O. phosphate phosphate esterester Load (1b.):

EXAM PLE II Mm. of foam Phosphate ester 0 min. 1 min. 5 min.

(1) Phenol plus 4 moles E.O .1 5 0 0 (2) Phenol plus 8 moles E.0 25 .5 27O 55 50 (3) Antala LS-500 1 1 A phosphate ester prepared from anethoxylated long chain aliphatic alcohol and sold under this designationby General Aniline and Film Corp.

Again, to demonstrate the low foam characteristics of the phosphateesters used in accordance with the present invention, the followingDynamic Foam Test data are given. This test generally involves stirring100 ml. of test solution at high speed and measuring the foam volume atequal time intervals. For details of the procedure see Journal of theAmerican Oil Chemists Society, 31, 254 257 (1954) DYNAMIC FOAM TESTMaximum foam volume Foam (5 min.

generation stirring Phosphate ester rate time) (1) Phenol plus 4 moleE.O 7. 5 15 (2) Phenol plus 8 mole E.0 17. 5 20 40 (3) Antara LS-500 1Example 'III The triethanolamine salt of the phosphate ester of a 4 moleethylene oxide adduct of phenol was tested for corrosion inhibitionproperties. In the test, 4 g. of cast iron chips are placed in ml. oftest solution (water solution) for 15 minutes with periodic swirling. Atthe end of the 15 minute interval, the solution is decanted 011 and theexcess liquid is removed by placing the chips on absorbent paper. Themoist chips are then examined visually for rusting.

Conc. test solution: Rusting 0.1% Slight. 0.5% None. 1% None. 2% None.

and

where n is an integer from about 3 to 5.

3. A composition according to claim 1, wherein the amine is a lowermolecular weight alkonalamine.

4. A composition according to claim 3, wherein the alkanolamine istriethanolamine.

5. A lubricant composition according to claim 1, containing about 0.1 toabout 0.2% of the triethanolamine salt of a phosphate ester selectedfrom the group of esters of the following formulae:

5 6 6. A method of effecting lubrication in metalworking ReferencesCited operations which comprises applying to the metal surface UNI EDSTATES A S undergoing working a lubricant in accordance with 3,310,4893/1967 Davis 252 325 claim 1.

7. A method of effecting lubrication in metalworking 5 DANIEL WYMANPnmary Exammer operations which comprises applying to the metal surfaceI. VAUGHN, Assistant Examiner undergoing working a lubricant inaccordance with CL claim 5. 72-42; 25249.3

